Responsive Polymer Brushes to Prevent Adhesion of Biopolymers
To develop a molecular tool kit for tailored brush structure that respond to stimuli and thus function on demand to prevent biofilm adhesion or ease of removal
Selected ESR: Silvia Ruscigno
Supervisor Name: Wuge Briscoe
Industrial Supervisors: Anju Brooker, Eric Robles
Recruiting Organisation: University of Bristol, UK
Hydrophobic surfaces are widespread in industrial and personal care products (e.g. on domestic appliances and clothing) and are particularly vulnerable to fouling (protein and bacterial adsorption), leading to biofilm formation and loss of material functions and performance. Current anti-biofouling strategies rely on the release of biocidal compounds, which can generate adverse environmental effects or consumer experiences. Therefore, non-toxic anti-fouling technologies without active chemicals have garnered interest in both medical and industrial fields. For instance, hydrophilic polymer brushes that are polymers end anchored on a surface with their chains stretching out, may effectively inhibit protein and bacterial adhesion via the excluded volume effect and hydration repulsion. Moreover, the discovery of reversible switching by external stimuli in polymer brushes has offered exciting possibilities for fabrication of adaptive and responsive interfaces. A highly desirable property in practical anti-fouling applications is that the brush system can be renewed or replenished. In this context, the “zipper brush” is a promising system, comprising dense neutral brushes in aqueous solution “zipped on” via a charged anchor block to the oppositely charged polymer segment of another di-block copolymer on the surface. The responsiveness or renewability of the zipper brush is facilitated by a pH change which causes the complexes of oppositely charged polyelectrolyte chains to dissociate and the brush to “zip off”, acting as a sacrificial layer for easy removal of adsorbed foulants from an interface. In this framework, the ESR4 project is focused on the design and the characterization of a zipper polymer brush system by absorption on hydrophobic substrates with desirable properties (e.g. high grafting densities, stability, stimuli-responsiveness, etc.), able to prevent non-specific biomolecular and microorganism attachment on surfaces. To do so, the mechanistic understanding of the interfacial coacervation underneath the zipping on and off phenomena exploited by polyelectrolyte polymers in aqueous solution is crucial.